1. Field
Aspects of the present invention relate to a frame assembly extending a donor film, a method of manufacturing a donor film used in laser induced thermal imaging (LITI), and a method of manufacturing an organic light emitting device using the frame assembly, and more particularly, to a frame assembly capable of tightly extending the donor film, a method of manufacturing the donor film used in LITI by using the frame assembly, and a method of manufacturing an organic light emitting device.
2. Description of the Related Art
An organic light emitting device is a flat panel display device that includes an anode electrode, a cathode electrode, and an intermediate layer. The intermediate layer is interposed between the anode electrode and the cathode electrode and includes at least one organic light emitting layer. The organic light emitting device has a wide viewing angle, excellent contrast ratio, and high response speed. Thus, the organic light emitting device is regarded as a next generation display device.
According to whether a light emitting layer is formed of a polymer organic material or a low-molecular organic material, the organic light emitting device may further include one or more organic layers, other than the organic light emitting layer, selected from the group consisting of a hole injection layer, a hole transport layer, an electron transport layer, and an electron injection layer.
In order for the organic light emitting device to achieve full color representation, the organic layer of the organic light emitting device must be patterned. Patterning may be performed using a shadow mask method in the case of a low-molecular organic light emitting device, and an inkjet printing method or laser induced thermal imaging (LITI) is used in the case of a polymer organic light emitting device. When LITI is used, the organic layer can be minutely patterned and be applied to a large surface, which is advantageous for achieving high image resolution.
When an organic layer is manufactured using LITI, at least a light source, an organic light emitting device substrate (acceptor substrate), and a donor film are needed. The donor film has a base film, a light to heat conversion (LTHC) layer, and a transfer layer. Light emitted from the light source is absorbed into the LTHC layer of the donor film and is converted to heat energy. The converted heat energy causes a change in the adhesion force between the LTHC layer, the transfer layer, and the acceptor substrate. Thus, materials of the transfer layer of the donor film are transferred onto the acceptor substrate, thereby patterning an organic light emitting layer on the acceptor substrate.
Conventionally, a base film including the LTHC layer is manually cut to a predetermined size by using a device, such as a straw cutter. The cut base film is fixed to a frame using a tape or an adhesive, and then a transfer layer is formed on the base film fixed on the frame to become the donor film. Next, the donor film including the transfer layer is detached from the frame and put on a vacuum chuck having a vacuum hole. The donor film is aligned on the acceptor substrate while applying a vacuum force thereto, thereby transferring the transfer layer from the donor film onto the acceptor substrate by LITI transfer.
However, during the above conventional LITI transfer method, although the donor film put on the vacuum chuck is fixed to the vacuum chuck by applying a vacuum force thereto, it is not possible to tightly extend or stretch the flexible donor film. Accordingly, minute air gaps are formed between the donor film and the acceptor substrate. Due to these air gaps, it is not possible to exactly transfer the transfer layer from the donor film onto the acceptor substrate, thereby causing defects in the organic light emitting device. To address this problem, the donor film may be laminated on the acceptor substrate by using a roller, but minute air gaps are still formed between the donor film and the acceptor substrate because it is not possible to extend or stretch the donor film as tightly as necessary.